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G Ridgway

Publications and source records attributed to G Ridgway.

15 recordsLinked to original sources
PubMed2002

Serial passage of Chlamydia spp. in sub-inhibitory fluoroquinolone concentrations.

We investigated the in vitro development of fluoroquinolone resistance in Chlamydia trachomatis and Chlamydia (Chlamydophila) pneumoniae grown in McCoy cell monolayers in supplemented Eagle's minimum essential medium. With C. trachomatis, initial passages at sub-inhibitory fluoroquinolone concentrations did not affect fluoroquinolone susceptibility. However, after an initial lag of 10-24 passages (depending upon the fluoroquinolone used), fluoroquinolone resistance developed rapidly. The final fluoroquinolone MIC after a total of 30 passages was >256 times the MIC of the original wild-type strain with ofloxacin or ciprofloxacin passage. Analysis of the quinolone-resistance determining regions of two quinolone-resistant C. trachomatis mutants obtained after 30 passages showed that both isolates had a single serine to isoleucine substitution at amino acid position 83 in GyrA. In stark contrast, with C. pneumoniae no reduced fluoroquinolone susceptibility could be sustained, even after 30 passages with moxifloxacin or ofloxacin. With sparfloxacin passage, some indication of resistance was observed but no viable organisms could be isolated for further investigation. It is possible that fluoroquinolone-resistant C. pneumoniae are less able to survive than wild type, which may explain why resistance does not develop readily.

Anti-Infective Agents↗
PubMed2001

Sexual behaviour in Britain: reported sexually transmitted infections and prevalent genital Chlamydia trachomatis infection.

BACKGROUND: Studies of the epidemiology of sexually transmitted infections (STI) are largely based on surveillance data. As part of a national survey of sexual attitudes and lifestyles (Natsal 2000) in Britain, we estimated the frequency of self-reported STIs, and the prevalence of urinary Chlamydia trachomatis infection. METHODS: We did a stratified probability sample survey of 11161 men and women aged 16-44 years in Britain. Computer assisted self-interviews contained items on the nature and timing of previously diagnosed STIs. Half of all sexually experienced respondents aged 18-44 years were invited to provide a urine sample for ligase chain reaction testing for C trachomatis infection. FINDINGS: 10.8% of men and 12.6% of women reported ever having an STI, 3.6% of men and 4.1% of women reported ever being diagnosed with genital warts, and 1.4% of men and 3.1% of women reported previous infection with C trachomatis. 76% of men and 57% of women ever diagnosed with an STI had been to a GUM clinic. C trachomatis was found in 2.2% (95% CI 1.5-3.2) of men and 1.5% (95% CI 1.11-2.14) of women with age-specific prevalence being highest among men aged 25-34 (3.1%) and women aged 16-24 years (3.0%). Non-married status, age, and reporting partner concurrency or two or more sexual partners in the past year were independently associated with infection with C trachomatis. INTERPRETATION: We show substantial heterogeneity in distribution of reported STIs, and the demographic and behavioural determinants of prevalent genital chlamydial infection. The results have potentially wide application for proposed chlamydia screening programmes which, given the demonstrated prevalence, must now proactively seek to involve men.

Adolescent↗
PubMed2001

Diploma in Hospital Infection Control: a progress report.

The Diploma in Hospital Infection Control (DipHIC) was established by the Hospital Infection Society (HIS), the London School of Hygiene and Tropical Medicine (LSHTM) and the Public Health Laboratory Service (PHLS) in 1997 and has now completed two examinations. We outline progress since the announcement of the diploma and changes to the written examination and reflective portfolio. The reflective process is described and guidance provided to active infection control practitioners wishing to consider application for the diploma by accreditation of prior learning.

Certification↗
PubMed2001

PCR detection and molecular identification of Chlamydiaceae species.

Recent taxonomic developments, based on 16s and 23s rRNA gene sequences, have divided the family Chlamydiaceae into two genera and nine species, of which five have been found to infect humans. Few simple methods are available to detect and identify all species sensitively and specifically. In this study the suitability of the omp2 gene as a target for molecular identification of Chlamydiaceae is demonstrated. Phylogenetic analysis of partial omp2 gene sequences from all nine species agrees with the recently published taxonomic changes based on the ribosomal genes. The use of a family-specific PCR primer pair, which is able to amplify the 5' end of the omp2 gene from all Chlamydiaceae except some Chlamydophila pecorum strains, is described. Identification of all nine species was achieved using restriction fragment length polymorphism analysis with a single enzyme, AluI, confirmed by DNA sequencing. A PCR enzyme-linked oligonucleotide assay was developed which can detect a single chlamydial genome and may be applied to DNA extracts from any specimen or culture for the detection of single or mixed human chlamydial infection.

Animals↗
PubMed2001

The acceptability of urinary LCR testing for Chlamydia trachomatis among participants in a probability sample survey of sexual attitudes and lifestyles.

OBJECTIVES: To examine the factors that influence respondents' willingness to participate in urinary testing for Chlamydia trachomatis in a general population feasibility survey of sexual attitudes and lifestyles. METHODS: 199 sexually experienced, 18-44 year old participants, recruited as part of a larger (n=901) methodological study of sexual attitudes and lifestyles, were invited to provide a urine sample for chlamydial infection testing using ligase chain reaction (LCR) techniques. Analysis of the survey data and in-depth qualitative interviews were undertaken to explore the factors that influenced participants' decisions to participate. RESULTS: 143/199 (72%) participants agreed to provide a urine sample. The likelihood of providing a urine sample was reduced if other individuals were present in the home at the time of interview (OR 0.42, 95% confidence interval 0.20-0.90, p=0.03). Trust and rapport with the interviewer, understanding the aims of the test, sense of obligation, and perceived importance of the test were identified as additional influencing factors in the in-depth interviews. CONCLUSIONS: Survey respondents' uncertainty or embarrassment at participating in urine testing can be overcome if they are well informed, motivated by the potential health gain, and briefed by trained and confident interviewers.

Adolescent↗
PubMed2000

Changing procedures.

Explore the source record for details and available documents.

Dental Care for Chronically Ill↗
PubMed2000

Home screening for chlamydial genital infection: is it acceptable to young men and women?

OBJECTIVES: To determine the acceptability, to young men and women, of home screening for chlamydial infection. METHODS: We wrote to a random sample of 208 women aged 18-25 years and 225 men aged 18-35 years from three general practices, inviting them to undergo home screening for chlamydial infection. They were asked to return, by normal post, a urine specimen (for men and half of the women) or a vulval swab (other half of the women) for ligase chain reaction (LCR) testing for chlamydial infection. They were also asked to return a short questionnaire about risk status and the acceptability of this approach. RESULTS: The participation rate among the available sample was 39% for women and 46% for men (p = 0.3). However, among women, the rate was slightly higher (p = 0.05) for urine samples (47%) than for vulval swabs (32%). Six per cent of women and 9% of men declined to take part, while 42% of women and 33% of men failed to respond. Two men objected to receiving the package at home. We received few other comments, positive and negative in about equal measure. CONCLUSION: Home screening for chlamydial infection is a potentially efficient method of reaching young people who may have little contact with health services. Men were at least as likely as women to respond to this screening approach. Home screening might form a useful component of a future chlamydial screening programme in the United Kingdom.

Adolescent↗
PubMed1997

Comparison of two methods of screening for genital chlamydial infection in women attending in general practice: cross sectional survey.

OBJECTIVES: To estimate the prevalence of Chlamydia trachomatis in asymptomatic women attending general practice: to assess the potential of the ligase chain reaction as a screening tool; and to evaluate selective screening criteria. DESIGN: Cross sectional survey. SETTING: Four general practices in northeast London. SUBJECTS: 890 women aged 18-35 years attending general practice for a cervical smear or a "young well woman" check between October 1994 and January 1996. The women were tested for C trachomatis with confirmed enzyme immunoassay (endocervical specimens) and ligase chain reaction assay on urine specimens. MAIN OUTCOME MEASURES: Prevalence of C trachomatis infection in women aged 18-35 on the basis of each test; sensitivity and specificity of both tests in this population. RESULTS: Prevalence of confirmed infection was 2.6% (95% confidence interval 1.6% to 3.6%) in all women. Prevalence on the basis of enzyme immunoassay was 1.6% (0.8% to 2.7%), with a sensitivity of 60% and a specificity of 100%. Prevalence on the basis of ligase chain reaction was 2.5% (1.5% to 3.9%), with 90% sensitivity and 99.8% specificity. Screening all women aged < or = 25 and all women who had had two or more partners in the past year would have detected 87% (20/23) of infections. CONCLUSION: Ligase chain reaction on urine samples performs at least as well as enzyme immunoassay on cervical specimens in this low prevalence population. It offers potential as a non-invasive screening tool. A simple selective screening strategy might be appropriate and would be able to detect most cases of infection. However, a rigorous economic evaluation of possible screening strategies is needed first.

Adult↗
PubMed1993

A survey of undergraduate and continuing medical education about antimicrobial chemotherapy in the United Kingdom. British Society of Antimicrobial Chemotherapy Working Party on Antimicrobial Use.

1 A questionnaire about undergraduate teaching on antimicrobial chemotherapy was sent to academic Departments of Clinical Pharmacology, Pharmacology and Medical Microbiology throughout the UK. 2 Questionnaires about postgraduate lectures and information circulated to doctors about antimicrobial chemotherapy were sent to Drug Information Centres and Postgraduate Tutors throughout the UK. Review articles and editorials in general medical journals were assessed. 3 The median amount of core undergraduate teaching on antimicrobial chemotherapy was 13.5 h but the range was from 9.0 h to 102.0 h. Content was predominantly oriented towards drugs rather than diseases and towards prescribing in hospital rather than in the community. Most teaching was by formal lecture as part of a core programme. On a scale from 0 to 5 the median emphasis given to individual topics ranged from 2.50 to 3.75 but the range of emphasis given by individual medical schools was wide, for example from 1.00 to 4.50 for teaching on pharmacokinetics. 4 Postgraduate tutors identified advice from local specialists and requests from local practitioners as the most important determinants of content of continuing medical education. Material from drug information centres was predominantly oriented towards discussion of individual drugs rather than management of specific diseases and even this limited survey found evidence of duplication. The UK general medical literature contained a total of 112 reviews or editorials on antimicrobial chemotherapy covering a wide range of topics but these were not, and should not be assumed to be comprehensive. 5 Almost all doctors regularly prescribe antimicrobials and require education about the subject. Wide variations in current medical practice should be addressed explicitly through more extensive use of problem solving. The literature suggests that knowledge is most effectively disseminated through local networks of practitioners. There should be more national co-ordination of the content of information to be disseminated through the existing drug information networks.

Anti-Bacterial Agents↗
PubMed1990

Confirmatory assay increases specificity of the chlamydiazyme test for Chlamydia trachomatis infection of the cervix.

Enzyme immunoassays for the detection of chlamydial antigens are commonly used to diagnose Chlamydia trachomatis infection. As is true for all nonculture methods, the specificities of these tests are a concern. A confirmatory blocking assay (Abbott Laboratories, North Chicago, Ill.) was evaluated at four sexually transmitted disease test sites. This assay is designed to confirm true-positive Chlamydiazyme (CZ) specimens and to identify false-positive CZ reactions caused by cross-reacting bacteria. Cervical specimens were collected from 2,891 women. Chlamydia prevalence by tissue culture (TC) was 9.2% (266 of 2,891 specimens). Compared with TC, the sensitivity and specificity of CZ were 78.9% (210 of 266 specimens) and 98.2% (2,577 of 2,625 specimens), respectively. There were 48 CZ false-positive reactions. The direct fluorescent-antibody test (DFA) was positive for 31 of 48 false-positive reactions, indicating culture misses. Thus, when the standard was both TC and DFA, CZ sensitivity was 81.1% and CZ specificity was 99.3%. Of the 17 CZ-positive patients who were negative by both TC and DFA, 3 were negative on repeat CZ and 11 of 14 were identified as false positive by the confirmatory assay. The confirmatory test was positive for CZ-positive women who were positive by TC or DFA. Use of the confirmatory test, which increased the specificity to 99.9%, would increase confidence in positive CZ results and make the test more useful for screening populations with a low prevalence of C. trachomatis infection.

Adult↗
PubMed1988

In vitro activity of azithromycin (CP-62,993), a novel macrolide, against enteric pathogens.

Azithromycin (CP-62,993 [9-deoxy-9A-methyl-9A-aza-9A-homoerythromycin]) is a novel macrolide antimicrobial. In this study the in vitro activity of CP-62,993 has been determined against selected enteropathogens, including Clostridium difficile, and compared with that of erythromycin. MICs were determined using an agar incorporation technique in Mueller-Hinton medium, containing saponin-lysed horse blood at a final concentration of 10% v/v, with an inoculum of 10(4) cfu. CP-62,993 was considerably more active than erythromycin against Salmonella typhi (MIC90 4 and greater than 32 mg/l, respectively), S. enteritidis (MIC90 4 and greater than 32 mg/l), Shigella flexneri (MIC90 2 and 32 mg/l), Sh. dysenteriae (MIC90 2 and 32 mg/l), Sh. sonnei (MIC90 4 and 32 mg/l), Campylobacter jejuni (MIC90 0.12 and 1 mg/l), Vibrio cholerae (MIC90 0.25 and 8 mg/l), V. parahaemolyticus (MIC90 0.5 and 8 mg/l), Yersinia enterocolitica (MIC90 4 and greater than 32 mg/l), Escherichia coli-ETEC (MIC90 4 and 32 mg/l), E. coli-EIEC (MIC90 4 and greater than 32 mg/l), Plesiomonas shigelloides (MIC90 1 and 8 mg/l) and Aeromonas hydrophila (MIC90 4 and 32 mg/l). CP-62,993 (MIC90 2 mg/l) was slightly less active than erythromycin (MIC90 1 mg/l) against isolates of C. difficile. The results suggest a potential clinical role for CP-62,993 in the treatment of enteric infections where antimicrobial therapy is indicated.

Azithromycin↗